Engine pressure regulator



Oct. 30, 1951 C. H. JORGENSEN ET AL ENGINE PRESSURE REGULATOR 7 Sheets-Sheet 1 Filed May 4, 1946 ATTORNEYS Oct. 30, 1951 c. H. JORGENSEN ET AL 2,572,865

ENGINE PRESSURE REGULATOR Filed May 4, 1946 Q 7 Sheets-Sheet 2 INVENT R5 mm a a zgmwfl I \M\ I Y M/FJA as $52 ATTORNEYS 0d. 30, 1951 c JORGENSEN ET AL 2,572,865

ENGINE PRESSURE REGULATOR 7 Sheets-Sheet 5 Filed May 4, 1946 IIIIIIII l), '9

an a-E r0 AIR INTAKE [W nfi/ I ATToRNEYy A Oct. 30, 1951 c. H. JORGENSEN ET AL 2,572,855

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Oct. 30, 1951 c. H. JORGENSEN ET AL 2,572,865

ENGINE PRESSURE REGULATOR Filed May 4, 1946 '7 Sheets Sheet 6 INCREASES PRESSURE WHEN ANTI DETO/VANT l5 SUPPLIED f0 SUPPLY or ANTI DETO/VA/VT ages \ INCHES bf INVENTORS ATTOR N EY$ v 0 6' [0 If Z0 29' J0 40 47.50

Oct. 30, 1951 c. H. JORGENSEN ET AL 2,

ENGINE PRESSURE REGULATOR Filed May 4, 1946 '7 Sheets-Sheet 7 /IIIIIIIIIIIIIIIIIIIIQ W 2': INVEgTZRS I ATTORNEY:

Patented Oct. 30, 1951 ENGINE PRESSURE REGULATOR Clarence H. J orgensen and Lawrence C. Dermond, Rochester, N. Y., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 4, 1946, Serial No. 667,442

11 Claims.

This invention relates to a pressure regulator for a supercharged internal combustion engine for airplane use.

An object of the invention is to provide for manual control of intake pressure selection accordin to a normal schedule suitable for use during operation of an auxiliary supercharger at relatively low speed (hereinafter termed low blower operation) in combination with means for automatically modifying the schedule in order to obtain a pressure schedule suitable for use during operation of the supercharger at relatively high speed (hereinafter termed high blower operation) and with means for limiting the intake pressures to values such that the engine will not detonate when liquid injection is not used and with means for automatically nullifying the limiting means when liquid injection is used.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments-of the present invention are clearly shown.

In the drawings:

Fig. 1 is a side view of the control embodying the present invention.

Fig. 2 is an end view in the direction of arrow 2 of Fig. 1.

Fig. 3 is a fragmentary bottom view in the direction of arrow 3 of Fig. 1.

Fig. 4 is a side view in the direction of arrow 4 of Fig. 2.

Fig. 5 is an end view in-the direction of arrow 5 of Fig. 4.

Fig. 6 is a sectional view on line 6-6 of Fig. 4.

Fig. 7 is a sectional view on lines 1--| of Figs. 2 and 5.

Fig. 8 is a sectional view on. lines 8---8 of Figs. 2 and 5.

Fig. 9 is a longitudinal sectional view of the tandem bellows shown in Fig. 7, and is drawn to a larger scale.

Fig. 10 is a sectional view on lines Ill-40 of Figs. 1 and 4.

Fig. 11 is a sectional view on line lI-ll of Fig. 1.

Fig. 12 is a sectional view on line l2l2 of Fig. 10.

Fig. 13 is a sectional view on line l3l3 of Fig. l2 and is drawn to a larger scale.

Fig. 14 is a sectional view on line l4l4 of Fig. 17.

Fig. 19 is a sectional view on line Ira-l9 of Fig. 4.

Fig. 20 is a fragmentary sectional view on line 20-20 of Fig. 19.

Fig. 21 is a fragmentary sectional view on line 2l2l of Fig. 19.

Fig. 22 is a sectional view on lines 22-22 of Figs. 1, '7 and 8.

Fig. 23 is a diagram of connections with one of the servo cylinders.

Figs. 24 through 28 are diagrams and Fig. 29 is a chart showing the operation of the regulator.

Figs. 30 and 31 are views similar to Figs. 12 and 25 showing a modification.

Fig. 32 is a sectional view on line 32-32 of Fig. 30.

Referring to the drawings, the regulator housing 30 provides an opening at its left end, Fig. '7, closed by a plate 31, opening in its right end closed by a plate 32 and parts supported thereby, and an opening in its left side (Fig. 10) closed by a plate 33. Housing 30 and plate 33 support, respectively, bearings 34 and 35 for a main control shaft 36 which is operated by the pilot through means connected with a lever, not shown, attached to the shaft 36. Since the shaft 36 is operated to select pressures to be maintained, the pressures corresponding to various positions of the'shaft are indicated by dial 38 (Fig. 1) supported by plate 33 and indicated by a pointer 39 attached to the shaft 36 as shown in Fig. 10.

Shaft 36 is operated also to control the engine throttle valve V, Figs. 1 and 4. Valve V is a butterfly valve located in a pipe P connected with the engine intake. Valve V is supported by a shaft S connected with a lever arm A which is connected by an adjustable link L with a throttle operating lever 40, Figs. 4 and 5. Lever 40 is supported by shaft 4| journalled in bearings 42 and 43 (Fig. 11) supported respectively by housing 30 and cover 33. To the shaft 4| there is fixed an arm 44 (Fig. 8) having a lug 45 for engagement with a stop screw 46 supported by the housing 30 and locked in adjusted position by a self-locking nut 41. Screw 46 limits movement of arm 44 to that required for full opening of the throttle V as indicated by V' in Fig. 4.

Arm 44 carries a stud 48 providing pivotal connection with a link 49 which is connected by a stud 50 with a floating lever 5| which is shown in Fig. 10 and is made of two metal stampings welded together. Lever 5| provides a slot 52 for receiving a roller 53 mounted on a stud 54 and retained by washer 55, Fig. 10, and a-nut 56 threaded on stud 54. Stud 54 is carried by an arm 51 attached to shaft 36 and engageable with either of two stop screws 58 locked in adjusted position by lock nuts 59. Screws 58 limit the movement of lever 51 to a predetermined range. It is apparent that rotation of shaft 36 will effect movements of lever 5|, link 49, lever 44, shaft 4|, arm 40, link L, arm A and valve V.

Lever 5| is operated also by'a servo motor comprising a cylinder 60, a piston 6| within the cylinder and urged normally toward the right, Fig. 8, by a spring 62 located between the piston 6| and the plate 3|. Piston BI is connected with a piston rod 63 guided by bearings 64 and 65 provided by the housing 30. Rod 53 is connected with lever 5| by a pin 66.

Referring to Fig. '7, housing 30 provides three parallel vertical passages 10, II and I2 closed at their lower ends by plugs I3 and opening at their upper ends into a horizontal bore I4 provided for the reception of a valve guide 15 having annular grooves 80, 8| and 82 registering, respectively, with passages I0, II and I2. Guide I5 provides a shoulder I6 engaging a recess II of the housing 30. Shoulder I6 is yieldingly retained within the recess II by a spring washer I8 retained by a snap ring I9 fitted into a groove provided by the valve guide I5. As shown in Figs. 7 and 10, the grooves 80, 8| and'82 are connected respectively with an internal bore 83 of the valve guide groups of radial ports (six in each group) marked respectively, 80a, BIa and 82a. The ports 8|a and 82a are controlled respectively by the lands 9| and 92 of a valve 93 received by the bore 83. Valve 93 controls the flow of pressure while entering through passage I to either of the passages II or I2. Passage II is connected, as shown diagrammatically in Fig. 23, by passages 84 and 85 with the right end of the cylinder or with the left end of the cylinder, as shown in Fig. 8. Passage I2 is connected by passages 86, 81 and 88 (Fig. 23) with the left end of the cylinder or with the right end as shown in Fig. 8. Passage I0, Figs. '7 and 10, is connected with a cross passage 89 to which a connection with oil pressure can be made in one of two ways, namely, by a pipe connected with a threaded opening 89a or by a passage indicated in dot and dash lines 8917 provided in a suitable mounting pad not shown. If such mounting pad is used, the opening 89a would be plugged. If such mounting pad is not used, the lower end of the passage 890. would be plugged by the bracket B to which the regulator is attached.

Referring to Fig. '7, the portion of the housing to the left of the partition 30a provides a chamber for receiving oil discharged from the left end of cylinder 60, Fig. 8, whenpiston -6I moves left, thereby forcing the oil from the left end of cylinder 60 out through the passages 84 and II and through the left end of bore'83 of guide I5. While the engine is operating the oil will rise to the level of the top surface 30b of partition 300. and flow toward the bottom of that portion of the housing 30 to the right of partition 30a. That portion is connected as shown in Fig. 1 with a drain pipe connected with a tapped opening 250. The discharge of the right end of cylinder 60 when piston 6| moves right through passages 88, 81, 86 and I2 out through the right end of the bore 83 of guide I is received by that portion of the housing to the right of partition 30a. When the engine stops and engine lubricating oil ceases to flow into the regulator, the oil accumulated in chamber 300 drains to chamber 30d through a small passage 306, Fig. 20.

Valve 93 is attached by a flexible rod 94 to a clevis 95 connected by a pin 96 with a lever 91 pivoted at 98 on a bridge 99-connecting the adjacent movable plates I00 and N0 of bellows I0| and III respectively. Bellows IOI is connected with a fixed plate I02 having its cen tral boss I03 received by ahole I04 provided by plate 3|, Fig. '7. Hole I04 is screw-threaded to receive a tubular screw I05 providing a screwdriver slot I05a. The position of the right end of screw I05 determines the position of the boss I03 and hence the position of the left plate |02 of the bellows IOI. The boss I03 is maintained against the right end of screw I05 by a screw I05 which passes through a plain hole in the screw I05 and which threadedly engages a central hole tapped in the boss I03. Screw I00 retains a cap |06a providing access to the screw I05. If screw I06 is removed cap |06a may be removed to permit adjustment of screw I05 which is retained in the desired position of adjustment by a self-locking nut IOEb.

. Bellows |0I is evacuated and its collapsing is resisted by springs I0! and I08 located between the ends I00 and I02. Bellows III is attached to a fixed ring I I2, attached by screws, such as M3, to a wall 30a of housing 30 and sealed thereto by a gasket I|4. Ring 2 is provided with an internal annular groove for receiving a snap ring II5 which retains a washer I|6 providing a seat for a spring II'I confined between plate H0 and ring H2. Bellows III is responsive to engine intake pressure. Since bellows II I and I0| have the same area and number of convolutions, the movement of the bridge 99 is controlled only by the pressure in the bellows I I I. The springs I01, I08 and III are so constructed and calibrated that the relation of positions of bridge 99 to pressures within the bellows III is substantially a linear relation. Bellows III is placed in communication with the engine intake through a passage I20 extending through the ring H2, gasket 4 and the partition 30a and connected with a passage I2 I, Fig. 22, which may be placed in communication with the engine intake in either of two ways namely, by a pipe, not shown, connected by a fitting which screws into a threaded opening I2 Ia or by a cross passage I22 which would be aligned with an opening I23, indicated by dot and dash lines if a mounting pad for the regulator were provided with such a passage connected with the engine intake. If such a mounting pad were not used, the passage I22 would be blocked by a mounting bracket, and passage I2I would be connected with a pipe having a fitting screwed into the threaded opening I 2| a.

The valve controlling lever 91 is positioned by the bridge 99 and also by a pressure selecting cam I30, Fig. '7, pivoted on a pin I3I carried by an arm I32 attached to the main control shaft 30 and providing a strut I33 against which the cam I30 is urged by a spring I34 connecting the cam with a lug I35 of the arm I32. Normally the cam I30 engages the strut I 33. Cam I30 cooperates with a cam follower roller I36 mounted on a stud I3I supported by a lever arm I38 which, as shown in Fig. 22, is attached to a hub sleeve I39 journalled 7) so that its normal position is that indicated by dot and dash lines I46, motion of the lever toward the right being limited due to its engagement with a housing member 232 to be described. Lever I46 is moved into the position shown in full lines in Fig. 7, when arm 44, Fig. 8, is moved into the dot and dash line position 44' which is its position when the throttle valve is fully opened. As arm 44 moves clockwise toward the position 44', its left hand edge indicated by line 44a, Fig. 7, engages a lug I 50 provided by arm I46. Therefore arm I46 will be located in the position shown in full lines in Fig. 7 when arm 44 is in the dot and dash line position 44' (Fig. 8) corresponding to which position the throttle valve is fully opened. Therefore when the throttle valve is fully opened, arm I43 is in such position as to cause movement of the valve 93 to the equilibrium position shown in Fig. 7, said movement of valve 93 being effected by the engagement of its right end by a screw II supported by lever I46 and secured thereto by lock nut I52. Therefore the servomotor is hydraulically stopped in the wide open throttle position, and cannot move the valve V past the position V' (Fig. 4).

The control of the throttle valve by shaft 36 alone is such as to obtain intake pressures sufficient for ascent from sea level Or for a safe landing in case of failure of the throttle servo. In the event of failure of oil pressure in cylinder 60, the spring 62 returns the piston 6| to the right of position, Fig. 8, thereby allowing a safe landing to be made through control of the throttle by shaft 36. The throttle is opened manually through the shaft 36 an amount less than required to maintain a selected pressure. The opening required to maintain selected pressure is effected by further opening of the throttle by the throttle servo as altitude increases. A greater throttle opening is required in order to maintain a selected pressure. For all pressure selections within the operating range, the throttle servo adds whatever opening movement of the throttle is required to maintain the selected pressure up to critical altitude. At critical altitude for all selected pressures within the operating range, the throttle is substantially wide open (as indicated by line V-W In Fig. 29). When the pressure selection is that required for minimum cruise. practically a full stroke of the servo piston 6| toward the left is required to open the throttle wide open. Since movement of the cam I30 clockwise to select pressures higher than required for minimum cruise is accompanied by manually effected opening of the throttle valve, less than full stroke of the piston 6| will be required to move the throttle valve to fully open position at critical altitudes. The amount of the stroke of the pistonrequired fully to open the throttle is determined by the movement of the valve 93 to equilibrium position as effected by lever 44 which moves lever I48 which moves ston screw I5I which locates the valve 93 in equilibrium position as shown in Fig. '7, thus providing an hydraulic stop or look. If the piston 6| were not hydraulically locked it would tend to change the position of shaft 36 although shaft H is blocked clockwise by the stop screw 46.

The cam I30 selects pressures according to a predetermined schedule of pressure positions of shaft 36 as slsawn in Fig. 1. The positions of shaft 36 and corresponding manifold pressures are indicated on the dial 36. These are the pressures which are obtained so long as the cam I30 engages the strut I33, Fig. '1. Under certain supported by lugs I69 and conditions, as will be explained, it is desirable to modify this schedule. This is obtained by moving the cam I30 about the pivot I3I. For example, if the cam I30 is moved into the position I30 (Fig. 25) wherein it is separated from strut I33, the normal schedule will be modified, that is, the schedule will be that represented by lines E-F--C, Fig. 9, instead of the normal schedule A-B-C. Cam I30 is provided with an auxiliary cam surface I30a normally out of engagement with a roller I60 in all positions of the cam I30 from zero to the position shown in Fig. 24. However, when the roller I60 is moved into the position I60 (Fig. 25) cam surface I30a is engaged by roller I60 and cam I30 is variably positioned away from the strut I33 depending on the contour of surface I30a; thus, modified schedule according to line EF--C or any other line below ABC may be obtained. Roller I60 is rotatable on a pin I6I (Fig. 14) which is supported by a plate I62 attached to a shaft I63 journalled in a tubular boss I64 provided by housing 30. The pin I6I is eccentric to the axis of the shaft I63. The shaft I63 may be operated in one of two ways, namely, by a lever I65 attached thereto or by means operatively con nected with the plate I62. In either case, rotation of the shaft I63 is limited by the engagement of an arm I66 (Fig. 4) of lever I65 with either of two adjustable stop screws I61 and I66 I10 integral with housing 30 and fixed in adjusted position by self-locking nuts HI and I12. If the shaft I63 is not manually operated through the lever I66, it is automatically operated by a servo-motor comprising a cylinder I15 (Fig. 12) provided by housing 30 and receiving a piston I16 carrying a wrist pin I11 for receiving a hub I16 of a link I19 (Fig. 13), connected by pin I60 with a lever I6I having a hub I62 (Fig. 14) journalled on a stud I63 carried by housing 30 and retained by a self-locking nut I64 threaded on the stud I63. A pin I65 (Fi 15) pivotally connects lever IBI with a link I66 connected by a stud I61 with an arm I66 integral with an offset portion I89 connecting arm I66 with plate I 62. A spring I90 (Fig. 12), which connects lever I6I with housing 30, urges the piston I16 left and lever I6I clockwise, lever I6I being held in the position shown in Fig. 12 so long as pressure fluid occupies the cylinder I15. This pressure fluid is the same as that'which actuates the throttle servo.

Referring to Fig. 18, passage 10, which is connected with a pressure oil source, is also con nected by passage I9I with a passage I92 (Fig. 1'?) leading, to the left end of cylinder I15 (Fig. 12). The connection between passages I9I and I92 is controlled by a piston valve I93 received by a cylinder I94 provided by housing 30 (Fig. 17). The valve I93 is normally held down against a retainer plate I95 (attached by screws I96 to housing 30) by a spring I93a. When it is desired to raise the valve I93, pressure fluid is admitted to the lower end of cylinder I94 through a passage I91 which is connected with a fluid pressure source in either of two ways, namely. a pipe connected by a coupling threaded'into the tapped hole I96 or through a side passage I99 communicating with a passage 200 provided by a mounting pad, not shown. When pressure fluid is admitted to the lower end of cylinder I94 sufficient to overbalance the pressure upon the valve I93 exerted by spring I93a and oil pressure above, the valve I93 is lifted so that its upper end blocks the passage I9I and passage I92 is connected with drain through a central bore 20l in valve I93, sidepassages 202, groove 203 and passage 204 leading to drain through the interior of the housing. The admission of pressure fluid through the passage I81 may be controlled in any manner and for any purpose. For example, when the transmission between the engine and the auxiliary blower is shifted into high gear, a valve is opened to cause pressure fluid to flow through pipe I91. Therefore, the regulator provides for coordinating the shift into high blower with a modification of the pressure selection to obtain the schedule represented by line E-F-C.

The full normal schedule ABC and the full modified schedule E-F-C are obtained only when liquid-injection is used to cool the fuel mixture so as to avoid detonation. Except at C, the pressure values on schedule E-FC are lower than those on schedule ABC. Since high blower operation increases the temperatures of the fuel-air mixture, it is necessary to lower the pressure selections in order to avoid detonation. As the pressure range FC is used in emergency for ascent to high altitude when outside air temperature is relatively low, it is possible to increase pressure selection to C without detonation. Up to the 65 position of cam I30, the portion AB of the normal schedule and the portion E-F of the modified schedule are obtained regardless of absence of liquid-injection. From the 65 to the 80 position of cam I30, the normal schedule is B-D and the modified schedule is FG. The limitation of the pressure obtainable without liquid-injection is effected by a cam-follower limiting stop lug 2I0, (Figs. 12 and 24) provided by a lever 2I I which is loosely journalled on shaft I63 and having a stop surface 2I2 normally engaged by the offset I89 of the arm I88 which extends from plate I62 (Figs. 14 and 15). A spring 2I3 (Fig. 12) connecting lever 2| I with an eye 2 I4 attached to housing 30, urges lever 2 against the offset I89 which cannot move from the positions shown in Figs. 12 and 24 since it is held in that position by the fluid pressure to the left of piston I16. In the position of lever 2 shown in Figs. 12 and 24, the stop lug 2I0 engages the cam follower roller pin I31 after cam I30 leaves the 65 position when moving toward the 80 position, shown in Fig. 24. Therefore the highest normal pressure selection without liquid-injection is B (for example about 52" Hg). In case f high-blower operation without liquid-injection, movement of piston I16 to I16 (Fig. 25) causes arm I88 and its offset I89 to move to I88 and I89; thereby freeing lever 2I I which is moved to position 2I I by spring 2 I3, said movement being arrested by the engagement of a pin 2 I on lever 2I I with the right end wall of a slot 2I6a of a link 2I6 used for a purpose to be described. Stop 2I0 is located at 2 I0 in Figs. 25, 26 and 27. From the zero position of cam I30 (at I30) in Fig. 25 to the 65 of the cam in Fig. 26, the roller I36 follows the cam. From the 65 position to the 80 position of the cam I30 (wherein it returns to the strut I33 in Fig. 27), the stop 2I0 (at 2I0') engages the pin I31 and prevents the roller I36 from following the cam I30. Therefore the highest obtainable pressure of the modified schedule is F or about 4'1" Hg. Without liquid-injection, the modified pressure schedule for high blower operation is FG between the 65 and the 80 positions of cam I30. Therefore detonation of the engine is prevented when liquid-injection is not present.

When liquid-injection is present the stop lug 2I0 is moved clockwise away from th roller pin I31 so that the regulator may operate according to the full normal schedule ABC for low blower operation and the full modified schedule E-FC for high blower operation. The retraction of stop lug 2I0 is effected automatically by the movement of a diaphragm 220 from the position shown in Fig. 25 to the position shown at 220' in Fig. 28. The periphery of the diaphragm 220 is clamped between the plate 32 and a plate cover 22I which provides, together with the diaphragm, a liquid chamber 222 to be connected with a source of liquid injection fluid under pressure through a pipe connected with the tapped hole 223 and passage 224. The central portion of the diaphragm 220 is located between the washers 225 which are located between washers 226. A rod 221 having a shoulder 228 passes through the washers and diaphragm and threadedly engages a selflocking nut 229 thereby clamping the diaphragm and washers against the shoulder 228. Rod 221 provides a diaphragm stop which engages a stop screw 230 threaded through the cover 22I and secured in adjusted position by a self-locking nut 23 I. The rod 221 may be urged toward the screw 230 by spring 2201) alone or by spring 22% plus the fluid pressure at the left of the diaphragm, said fluid pressure being confined within a chamber provided by the diaphragm, the plate 32 and a cover 232 clamped against a shoulder 233 of plate 32 by screws 234. The space to the left of diaphragm 220 may be placed in communication with a fluid pressure source such as the engine air scoop or other part which is subjected to ram pressure by a pipe connected with the tapped opening 235, (Fig. 8), in plate 32 and connected by a passage 236 with the space between the cover 232 and the diaphragm 220; or the opening 235 may be plugged and the air scoop may be connected with said space through a duct in a mounting pad communicating with hole 231 (Fig. 3) connected by passages 238 and 239 with passage 236.

When liquid injection is used during high blower operation, the pressure of the injectionliquid at the right of the diaphragm 220 overcomes spring 220b (and also ram pressure at the left of the diaphragm in case the space at the left of the diaphragm is connected with the air scoop), and the diaphragm moves from the position shown in Fig. 25 to that shown in Fig. 28, thereby causing left movement of rod 221 and link 221a, clockwise movement of lever 240, shaft 24I and lever 242 connected therewith, and left movement of link 2I6. As link 2I6 moves left from the position shown in Fig. 25'to that shown in Fig. 28, the right end of its slot 2I6a presses against the pin 2I5 of lever 2 to cause said lever to move against the action of spring 2I3 from the position 2I I (Fig. 25) to the position 2II (Fig. 28), thereby retracting the stop lug 2I0 from engagement with the cam follower roller pin I31, thereby permitting the cam follower roller I36 to follow the cam IIO into any of its positions. When liquid injection is present, in the range of 65 to positions of cam I30, the pressure schedule is BC for low blower operation and the pressure schedule is FC for high blower operation. When liquid injection ceases, the schedules in the 65-80 range automatically become BD for low blower operation and F-G for high blower operation, since the spring 220?) automatically returns the diaphragm 220 to the position shown in Fig. 25. thereby returning the lug 2I0 to its cam-follower-pin-limiting position.

As stated before, the piston I16, Fig. 12, is

' held in the position shown for low blower operation by pressure fluid in cylinder I15 which resists the action of spring I90. By relieving the oil pressure in cylinder I15, the spring I90 moves the piston I16 to the position I16 (Fig. 25) for high blower operation. In order to provide for such control of the piston I16, it is necessary to provide the shuttle valve I93 (Fig. 1'1) which is lifted by pressure fluid in pipe I91 in order to provide for the relief of pressure in cylinder I15. Fluid pressure in pipe I91 exists when high blower operation is called for. The advantage that flows from the use of the shuttle valve I93, isthat failure of oil pressure in the cylinder I15 will not result in engine detonation. For example, if at the time of low blower operation, the pressure selection is on line B-D and oil pressure in ducts 10, I9I and I92 (Fig. 18) should fail, the spring .90 will move the piston I16 (Fig. 12) to I16 (Fig. 25) thereby lowering the pressure to FG. Obviously, if the oil pressure in pipes and I9I drops during high blower operation when duct I9I is blocked by shuttle valve I93 and the cylinder I15 is connected with drain, there will be no change in the position of piston I16 and the pressure selection wil still remain on line FG. The apparatus is therefore safe to use in systems when failure of oil pressure during high blower operation does not automatically effect the return to low blower operation.

However, if the apparatus is to be used in a system wherein failure of oil pressure during high blower operation results in return to low blower operation automatically, the shuttle valve I93 is omitted and the apparatus is simplified as shown in Figs. 7") to 32. The cylinder I15 is connected by duct I922: with the source of oil pressure which is effective to cause the shift from low blower to high blower operation. Therefore, when shifting from low blower to high blower, this oil pressure shifts the piston I16 from the position shown in Fig. 30 to the position shown in Fig. 31. This causes, through the action of link I19, lever I8I:r, link I86:c and lever I881; the separation of pad I893: from surface 2I2 of lever 2 thereby permitting lever III to move under the action of the spring 2I3 from the position shown in Fig. 30 for low blower operation to the position shown in Fig. 31 for high blower operation. If the pressure drops in cylinder I15 sufliciently to permit the spring I991 to return the piston I16 to the position shown in Fig. 30 there will be a return to low blower operation so that the pressure selection will change from a value on line EFG to a value on line A-B--D which is safe for low blower operation.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is understood that other forms might be adopted all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A pressure regulator for supercharged internal combustion engines comprising a device responsive to engine intake pressure, a pressure selecting cam, a cam follower, apparatus under joint control by the device and the cam follower for so adjusting an engine intake throttle valve as to maintain a selected pressure, a main control member for moving the cam into various positions of pressure selections according to a predetermined normal schedule of positions of the control member and pressures, means for effecting, as the cam is moved by the main control member, movement of the cam laterally relative to its direction of movement by the member whereby a modified schedule of pressure selections is obtained anda mechanism for rendering said means operative dr non-operative.

2. A pressure regulator for supercharged internal combustion engines comprisi'rigg. device responsive to engine intake pressure, a pressure selecting cam, a cam follower, apparatus unden joint control by the device and the cam follower for so adjusting an engine intake throttle valve as to maintain a selected pressure, a main control member for moving the cam into various posltions of pressure selections according to a predetermined normal schedule of positions of the control member and pressures, means for effecting, as the cam is moved by the main control member, movement of the cam laterally relative to its direction of movement by the member whereby a modified schedule of pressure selections is obtained, a mechanism for rendering said means operative or non-operative, a stop member positioned so as to prevent the cam follower from following the cam in the higher pressure selecting range of its movement, and means for retracting the stop member.

3. A pressure regulator for supercharged internal combustion engines comprising a device responsive to engine intake pressure, a pressure selecting cam, a cam follower, apparatus under joint control by the device and the cam follower for so adjusting an engine intake throttle valve as to maintain a selected pressure, a main control member for moving the cam into various positions of pressure selections according to a predetermined normal schedule of positions of the control member and pressures, means for effecting, as the cam is moved by the main control member, movement of the cam laterally relative to its direction of movement by the member whereby a modified schedule of pressure selections is obtained, a mechanism for rendering said means operative or non-operative, a stop member positioned so as to prevent the cam follower from following the cam into certain higher pressure selections of either the normal schedule or of the modified schedule, and means for retracting the stop member.

4. A pressure regulator for supercharged internal combustion engines comprising a device responsive to engine intake pressure, a pressure selecting cam, a cam follower, apparatus under joint control by the device andthe cam follower for so adjusting an engine intake throttle valve as to maintain a selected pressure, a main control member for moving the cam into "nous positions of pressure selections according to a predetermined normal schedule of positions of the control member and pressures, means for effecting, as the cam is moved by the main control member, movement of the cam laterally relative to its direction of movement by the member whereby a modified schedule of pressure selections is obtained, a mechanism for rendering said means operative or non-operative, a stop member normally positioned so as to prevent thecam follower from following the cam into a certain range of high pressure selections of the normal schedule and positioned by the mechanism when set to render said means operative, so as to prevent the cam follower from following the cam into a range of pressure selection of the modified schedule co-extensive with said range of the 11 normal schedule, and means for retractin the stop member from either position.

5. A pressure regulator for supercharged internal combustion engines comprising a device responsive to engine intake pressure, a pressure selecting cam. a cam follower, apparatus under joint control by the device and the cam follower for so adJusting an engine intake throttle valve as to maintain a selected pressure, a main control member for moving the cam into various positions of pressure selections according to a predetermined normal schedule of positions of the control member and pressures, means for effecting, as the cam is moved by the main control member, movement of the cam laterally relative to its direction of movement by the member whereby a modified schedule of pressure selections is obtained, a mechanism for rendering said means operative or non-operative, a stop member normally positioned so as to prevent cam follower from following the cam after the main control member passes a certain position during its movement toward the highest pressure selecting position, and positioned by the mechanism, when set to render said means operative. so as to prevent the cam follower from following the cam after the main control member passes said certain position of its movement, and means for retracting the stop member from either position.

6. A pressure regulator for supercharged internal combustion engines comprising a shaft, a cam bar pivotally supported by the shaft eccentrically thereof, a cam bar stop carried by the shaft, a spring urging the cam bar against the stop, saidcam bar having inner and outer cam surfaces, a cam-follower spring-urged into engagement with the outer surface, a device responsive to engine intake pressure, apparatus under joint control of the device and the cam follower for so adjusting an engine intake throttle-valve as to maintain a selected pressure, a main control member for turning the shaft in order to select pressures according to a predetermined normal schedule of positions of the control member and pressures, an element movable into engagement with the inner cam surface of the cam bar to cause it to move about its pivot as the cam shaft is turned thereby modifying the schedule of pressure selections and a mechanism for moving the element into operative or non-operative positions.

7. A pressure regulator for supercharged internal combustion engines comprising, a shaft, a cam bar pivotally supported by the shaft eccentrically thereof, a cam bar stop carried by the shaft, a spring urging the cam bar against the stop, said cam bar having inner and outer cam surfaces, a cam-follower spring-urged into engagement with the outer surface, a device responsive to engine intake pressure, apparatus under joint control of the device and the cam follower for so adjusting an engine intake throttle-valve as to maintain a selected pressure, a main control member for turning the shaft in order to select pressures according to a predetermined normal schedule of positions of the control member and pressures, an element movable into engagement with the inner cam surface of the cam bar to cause it to move about its pivot as the cam shaft is turned thereby modifying: the schedule of pressure selections, a mechanism for moving the element into operative or nonoperative positions, a stop member for preventing the cam follower from following the cam 12 into position of high pressure selection, and means for retracting the stop member.

8. A pressure regulator for supercharged internal combustion engines comprising a shaft, a cam bar pivotally supported by the shaft eccentrically thereof, a cam bar stop carried by the shaft, a spring urging the cam bar against the stop, said cam bar having inner and outer cam surfaces, a cam-follower spring-urged into engagement with the outer surface, a device responsive to engine intake pressure, apparatus under joint control of the device and the cam follower for so adjusting, an engine .intake throttle-valve as to maintain a selected pressure, a main control member for turning the shaft in order to select pressures according to a predetermined normal schedule of positions of the control member and pressures, an element movable into engagement with the inner cam surface of the cam bar to cause it to move about its pivot as the cam shaft is turned thereby modifying the schedule of pressure selections, a mechanism for moving the element into operative or nonoperative positions, a stop member positioned by the mechanism for preventing the cam follower from following the cam beyond a certain position of its angular movement toward highest selecting position, and means fofietracting the stop member from either of its positions.

9. A pressure regulator for supercharged internal combustion engines cmprising, a shaft, a cam bar pivotally supported by the shaft eccentrically thereof, a cam bar stop carried by the shaft, a spring urging the cam bar against the stop, said cam bar having inner and outer cam surfaces, a cam follower, a cam-follower support, a spring urging the cam-follower into engagement with the outer cam surface, a device responsive to engine intake-pressure, apparatus under joint control of the device and the cam follower for so adjusting an engine intake throttle-valve as to maintain a selected pressure, a main contro1 member for turning the shaft in order to select pressures according to a predetermined-normal schedule of positions of the control member and pressures, a second shaft, a second cam-follower eccentrically supported by the second shaft for engagement with the inner cam surface of the cam-bar, and a mechanism for rotating the second shaft.

10. A pressure regulator for supercharged internal combustion engines comprising, a shaft, a cam bar pivotally supported by the shaft eccentrically thereof, a cam bar stop carried by the shaft, a spring urging the cam bar against the stop, said cam bar having inner and outer cam surfaces, a cam follower, a cam-follower support, a spring urging the cam-follower into engagement with the outer cam surface, a device responsive to engine intake pressure, apparatus under joint control of the device and the cam follower for so adjusting an engine intake throttle-valve as to maintain a selected pressure, a main control member for turning the shaft in order to select pressures according to a predetermined normal schedule of positions of the control member and pressures, a second shaft, a second camfollower eccentrically supported by the second shaft for engagement with the inner cam surface of the cam-bar, a mechanism for rotating the second shaft, a lever loosely journalled on said shaft and providing a stop for engaging the cam-follower support to prevent the cam-follower from following the cam beyond a certain angular position thereof, means movable with 13 the mechanism for controlling the position of the stop lever, and means for retracting the stop lever for engagement with the cam-follower support in any position of the cam.

11. A pressure regulator for supercharged internal combustion engines comprising a device responsive to engine intake pressure, a pressure selecting means, apparatus under joint control by the means and by the device for positioning an engine intake throttle valve in order to maintain a selected pressure, a control member for moving the pressure selecting means to obtain a certain normal schedule of pressures corresponding to positions of said member, means for modifying the pressure selecting means to obtain a dif- 14 ferent schedule of pressures, means for limiting the pressures obtainable to values on either schedule corresponding to substantially the same position of the control member, and means for rendering the limiting means inoperative. CLARENCE H. JORGENSEN.

/ LAWRENCE C. DERMOND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Halford et a1. Oct. 8, 1940 Number 

